Flow line systems which transport potentially dangerous fluids, such as anhydrous ammonia, commonly include a separable connection for emergency interruption of the flow line which extends between tanks and/or a tank and a toolbar on a transport vehicle. With a tank to tank connection, for example, if one tank is pulled away from the other prior to disconnecting the flexible flow line, the absence of a separable connection may otherwise cause a rupture of the fill line.
The monetary loss of fluid from such a rupture is nominal compared to the danger of releasing toxic vapors. The release of anhydrous ammonia may seriously injure the operator, causing blindness, skin burns, or loss of smell. For other potentially dangerous fluids, such as propane and liquid petroleum gas, the release of the fluid may cause adverse environmental consequences to the filling station site or create a fire hazard.